The invention relates generally to a device appropriate
surgical treatment of benign prostate hyperplasia and more particularly to a balloon catheter appropriate for dilating a portion of the urethra constricted by an enlarged prostate gland.
Benign prostate hyperplasia (BPH) is a disease characterized by enlargement of the prostate gland. As the prostate enlarges, it compresses the urethra, impairs urination and can lead to urinary tract infection and possible renal failure. Surgical and non-surgical treatment of BPH have been proposed.
Surgical treatment of BPH typically involves transurethral resection of the prostate. This procedure requires 5 to 6 days of hospitalization and is associated with some morbidity. Balloon dilation of the prostate is emerging as an important non-surgical near-term treatment for BPH. It can be carried out under sedation and local anesthesia in about 20 minutes. In this procedure a balloon catheter is inserted through the urethra to the prostate and the balloon is inflated to compress the internal tissue and stretch the outer capsule of the prostate. The patient can return home with a Foley catheter in place for two days. The recovery period is usually 3 to 4 days.
An example of a balloon apparatus for treating BPH is described in U.S. Pat. No. 4,660,560. FIG. 1 is a cross-sectional view of a dilating catheter assembly 10 positioned in the male urinary tract. A multi-channel cystoscope 12 is received through penile meatus 14 and is positioned in urethra 16 in which dilating catheter 10 is passed through one of its lumens. An extended Foley-balloon 18 is anchored to bladder neck 22 while an annular balloon 20 is fixedly positioned with respect to the prostatic urethra as defined by bladder neck 22 and veru montanum 24. Pressure dilation of the prostatic urethra by annular balloon 20 continues as long as it is deemed necessary. U.S. Pat. No. 4,762,128 discloses al single prostate balloon catheter for imparting an expanded tubular stent to extend long term patency. Catheters such as these are not fully satisfactory since they require multiple instrumentations of the urethra and multiple components such as a sighting lens, sheath and dilation catheter. These are awkward to simultaneously position properly at the prostate. Such catheters can lead to improper dilation of the external sphincter or improper dilation beyond the bladder neck. Furthermore, a 26 F plastic sheath, which is undesirably large, is required to insert and withdraw the balloon and a lens.
Another example of a balloon catheter for treating BPH is described in European patent application No. 0,341,988. A location or positioning balloon is located proximal to a prostate dilation balloon along the catheter. The location balloon is positioned to be at the bulbous urethra when the dilation balloon is at the prostate urethra. This fixes the location balloon to be intermediate the external sphincter and bladder to maintain the dilation balloon in proper position when it is inflated at the prostate urethra. The location balloon is sized to fit the bulbous urethra on inflation to prevent undesirable dilation of the external sphincter.
The catheter described in the European patent application also has drawbacks. To position the dilation balloon properly, a fluoroscope or lens is required. The fluoroscope exposes the patient to unnecessary radiation and the lens must be inserted unguided alongside the catheter shaft, increasing the likelihood of deleteriously scraping the urethra. Either option makes the entire procedure undesirably complex.
Balloons for prostate catheters are commonly substantially not elastic. Accordingly, when the conventional balloon is to be removed, it must first be threaded into a sheath. This makes the procedure and device unduly complicated.
Accordingly, it is desirable to provide an improved balloon catheter for dilating the prostate to reduce constriction of the urethra which overcomes the shortcomings of available prostate balloon catheters.